Graphical user interface (GUI) controls, including GUI controls that allow touch input, are widely used. However, graphical elements have a certain size and can interfere with a viewing region where a user may prefer to focus on visualized data on the display. In addition, graphical elements such as toolbars and menus are often designed to be used from one direction. This works for some devices with a traditional screen where “up” and “down” are clearly defined for the users. The situation for collaborative work, particularly around a table top (horizontally oriented/mounted) display, is different. In this situation, the users are typically viewing the visualization from different directions. Thus, the notion of “up” and “down” on the screen space is not the same.
Conventionally, some GUIs included fixed dedicated areas of the screen area where alternative interactions are performed or started. The main problem with this approach is that, for collaborative purposes, fixed areas may not be accessible or reachable to all users of the collaborative session.
One of the main benefits with touch interaction is that the user is provided with the ability to interact with objects using touch gestures. However, in order to make intuitive, user-friendly user interfaces for an advanced application, a limited set of base features are directly available to the user and alternative or more advanced features are available only after they have been activated.
For 3D visualization software, for instance in the field or technology area of medical imaging, a base functionality that is immediately accessible to the user in a touch application would involve rotating and panning 3D objects around or in the direction of each of the three coordinate system axes, as well as uniform zoom. Additional features in medical visualizations, such as using tools for removing certain structures in the dataset or changing the current color mapping, require activation of some kind, for instance by setting the application in a certain mode or using graphical user interface controls that affect that dataset in a specific manner.
Unfortunately, a problem with putting an application in a specific mode is that users have to frequently switch modes in order to perform a desired action. For mode-based medical imaging software, it is not uncommon that a user has to switch between two modes several times in order to highlight a certain finding in the dataset. In addition, the mode-based approach is not recommend for displays providing collaborative work since it is difficult for participants of a collaborative session to follow mode changes.
Furthermore, for touch input, it is not uncommon that the same gestures are used in multiple or even all modes, meaning that the same user action triggers different features in the software depending on which mode the application is currently in. This can confuse users, especially if the application is used in a collaborative environment.
There remains a need for alternate GUIs that can allow for more intuitive and user-friendly interaction with users.